Now that alternative refrigerants for ozone-depleting fluorons are being discussed based on the Montreal Protocol, attention is turning towards refrigerating machine oils suitable for the alternative refrigerants. For example, synthetic oils for use with hydrofluorocarbons (HFC) are known such as polyol esters and ethers which are compatible with HFC refrigerants (e.g., Patent documents 1-3).    [Patent document 1] JP-A H03-505602    [Patent document 2] JP-A H03-128992    [Patent document 3] JP-A H03-200895